1. Field of the Invention
The invention relates to an arrow shaft.
2. Description of the Related Art
An arrow includes an arrow shaft with a hollow cylindrical shape and an arrow head being mounted in front of the arrow shaft, an arrow nock coupled to the rear end of the arrow shaft for fitting an arrow in the string, and a plurality of fletchings being mounted to a rear side of an outer circumferential surface of the arrow shaft and being radially spaced apart each other by two to four sheets.
In general, an arrow leaving a bow or a crossbow flies in an arc towards the target. During flying, the arrow is subject to shaking in every direction based on the center of gravity. In other words, the arrow does not fly straight toward the target and flies wobbly as fishes swim. This is referred to the paradox phenomenon. In order to prevent such a phenomenon, fletchings are provided for an arrow to fly straight by air resistance. Further, the arrow flies while rotating due to the effect of air resistance influenced by the fletchings, and the arrow with rotating is capable of flying much more stable than that of without rotating. That is, provision of a slight pitch to the direction of fletchings to be mounted to the arrow shaft causes the arrow with rotating to fly stably. This is referred to the gyro effect.
As described above, fletchings play an important role in the arrow. In general, fletchings may be mounted on the rear side of the outer circumferential surface of the arrow shaft with spacing apart by two to four sheets using adhesive, etc.
By the way, as most of tasks of mounting fletchings on the outer circumferential surface of the arrow shaft are carried out manually, it is difficult to mount fletchings by adhesive on the exact positions for fletching on the arrow shaft.
In connection with such a problem, Korean utility model Registration No. 20-0250124, entitled “MOUNTING DEVICE OF FLETCHING FOR ARROW” discloses a device of automatic mounting of fletchings. However, such a device still has a problem that arrows are not always used as manufactured.
In other words, many users who use arrows for hunting or competition not only use arrows which were manufactured and finished in the factory, but also use arrows with different configurations, shapes, positions and types of fletchings being mounted to arrow shafts according to shooting habits and skills of users. Thus, shapes and mounting positions of fletchings, as well as numbers and types of fletchings may be different each other for each user.
Accordingly, it has been needed to develop devices for users to mount fletchings accurately to the desired position of the arrow shaft.
In response to such a need, Korean Patent Laid-Open Publication No. 10-2008-0082878, entitled “SHAFT OF AN ARROW” discloses an arrow shaft having a plurality of fletching indication patterns with straight-line forms in parallel to the longitudinal central axis on the rear side of the circumferential surface of the arrow shaft.
However, there still remains a problem in the above approach with fletching indication patterns of straight lines, because it is not easy to set accurately the position around the front and the rear of axis direction where the fletchings will be mounted.